feat: Add sorting by contacts count to companies list (#13012)

## Description

Adds the ability to sort companies by the number of contacts they have
(contacts_count) in ascending or descending order. This is part of the
Chatwoot 5.0 release requirements for the companies feature.

The implementation uses a scope-based approach consistent with other
sorting implementations in the codebase (e.g., contacts sorting by
last_activity_at).

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## Available Sorting Options

After this change, the Companies API supports the following sorting
options:

| Sort Field | Type | Ascending | Descending |
|------------|------|-----------|------------|
| `name` | string | `?sort=name` | `?sort=-name` |
| `domain` | string | `?sort=domain` | `?sort=-domain` |
| `created_at` | datetime | `?sort=created_at` | `?sort=-created_at` |
| `contacts_count` | integer (scope) | `?sort=contacts_count` |
`?sort=-contacts_count` |

**Note:** Prefix with `-` for descending order. Companies with NULL
contacts_count will appear last (NULLS LAST).

## CURL Examples

**Sort by contacts count (ascending):**
```bash
curl -X GET 'https://app.chatwoot.com/api/v1/accounts/{account_id}/companies?sort=contacts_count' \
  -H 'api_access_token: YOUR_API_TOKEN'
```

**Sort by contacts count (descending):**
```bash
curl -X GET 'https://app.chatwoot.com/api/v1/accounts/{account_id}/companies?sort=-contacts_count' \
  -H 'api_access_token: YOUR_API_TOKEN'
```

**Sort by name (ascending):**
```bash
curl -X GET 'https://app.chatwoot.com/api/v1/accounts/{account_id}/companies?sort=name' \
  -H 'api_access_token: YOUR_API_TOKEN'
```

**Sort by created_at (descending):**
```bash
curl -X GET 'https://app.chatwoot.com/api/v1/accounts/{account_id}/companies?sort=-created_at' \
  -H 'api_access_token: YOUR_API_TOKEN'
```

**With pagination:**
```bash
curl -X GET 'https://app.chatwoot.com/api/v1/accounts/{account_id}/companies?sort=-contacts_count&page=2' \
  -H 'api_access_token: YOUR_API_TOKEN'
```

## How Has This Been Tested?

- Added RSpec tests for both ascending and descending sort
- All 24 existing specs pass
- Manually tested the sorting functionality with test data

**Test configuration:**
- Ruby 3.4.4
- Rails 7.1.5.2
- PostgreSQL (test database)

**To reproduce:**
1. Run `bundle exec rspec
spec/enterprise/controllers/api/v1/accounts/companies_controller_spec.rb`
2. All tests should pass (24 examples, 0 failures)

## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes

## Technical Details

**Backend changes:**
- Controller: Added `sort_on :contacts_count` with scope-based sorting
- Model: Added `order_on_contacts_count` scope using
`Arel::Nodes::SqlLiteral` and `sanitize_sql_for_order` with `NULLS LAST`
for consistent NULL handling
- Specs: Added 2 new tests for ascending/descending sort validation

**Files changed:**
- `enterprise/app/controllers/api/v1/accounts/companies_controller.rb`
- `enterprise/app/models/company.rb`
-
`spec/enterprise/controllers/api/v1/accounts/companies_controller_spec.rb`

**Note:** This PR only includes the backend implementation. Frontend
changes (sort menu UI + i18n) will follow in a separate commit.

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Pranav <pranav@chatwoot.com>

app/javascript/dashboard/components-next/Companies/CompaniesHeader/components/CompanySortMenu.vue

@@ -35,6 +35,10 @@ const sortMenus = [
     label: t('COMPANIES.SORT_BY.OPTIONS.CREATED_AT'),
     value: 'created_at',
   },
+  {
+    label: t('COMPANIES.SORT_BY.OPTIONS.CONTACTS_COUNT'),
+    value: 'contacts_count',
+  },
 ];
 
 const orderingMenus = [

app/javascript/dashboard/i18n/locale/en/companies.json

@@ -6,7 +6,8 @@
       "OPTIONS": {
         "NAME": "Name",
         "DOMAIN": "Domain",
-        "CREATED_AT": "Created at"
+        "CREATED_AT": "Created at",
+        "CONTACTS_COUNT": "Contacts count"
       }
     },
     "ORDER": {

app/javascript/dashboard/routes/dashboard/companies/pages/CompaniesIndex.vue

@@ -9,7 +9,7 @@ import { useCompaniesStore } from 'dashboard/stores/companies';
 import CompaniesListLayout from 'dashboard/components-next/Companies/CompaniesListLayout.vue';
 import CompaniesCard from 'dashboard/components-next/Companies/CompaniesCard/CompaniesCard.vue';
 
-const DEFAULT_SORT_FIELD = 'created_at';
+const DEFAULT_SORT_FIELD = 'name';
 const DEBOUNCE_DELAY = 300;
 
 const companiesStore = useCompaniesStore();
@@ -37,7 +37,7 @@ const parseSortSettings = (sortString = '') => {
   };
 };
 
-const { companies_sort_by: companySortBy = `-${DEFAULT_SORT_FIELD}` } =
+const { companies_sort_by: companySortBy = DEFAULT_SORT_FIELD } =
   uiSettings.value ?? {};
 const { sort: initialSort, order: initialOrder } =
   parseSortSettings(companySortBy);